<%--
  Created by IntelliJ IDEA.
  User: ghp
  Date: 2022/10/4
  Time: 10:35
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--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>c_out1</title>
</head>
<body>
userName的属性值为:
<c:out value="${param.username}" default="unknown"/><br/>
<c:out value="${param.username}">unknown</c:out>
</body>
</html>
